Projectors are often used in education activities or the like. Depending on different application scenarios, the projector is installed at different positions. In the case that an application scenario is changed, it is necessary to displace the projector (i.e., dismount the projector installed at one position and then install it at another position, so it is inconvenient to mount, dismount and use the projector), or purchase a new projector (resulting in an increase in the cost and the work load of installation).